1. Field of Invention
The present invention relates to a printed circuit board fastening mechanism. More particularly, the present invention relates to an expansion card fastening mechanism.
2. Description of Related Art
Referring to FIG. 1 and FIG. 2, two expansion card fastening mechanisms are illustrated to secure a short card and a long card. In order to satisfy the market demands, all electronic devices are made thin and equipped with various functionalities. For this purpose, component providers integrate each functionality into single one module card to enable each modulized functionality to be conveniently added onto an electronic device. For instances, the short card 110a and the long card 110b are module card. The card edge connectors 104 for engaging the short card 110a and the long card 110b are of the same size and specification. However, the baseboard 102 needs several screw holes and support columns to secure both the short card 110a and the long card 110b thereon. For example, columns 106a and screws 108 are used to secure the short card 110a on the baseboard 102, and columns 106b and screws 108 are used to secure the long card 110b on the baseboard 102. Since the columns 106a and columns 106b should be located differently to secure the short card 110a or the long card 110b on the baseboard 102, the baseboard 102 requires at least four screw holes. In case the columns 106a and columns 106b are simultaneously located on the baseboard 102 (see FIG. 3), the long card 110b would not be properly secured thereon because the columns 106a interfere the long card 110b. In addition, screw holes would reduce the area to be occupied by printed circuits. For the forgoing reasons, there is a need for improving the expansion card fastening mechanism.